Cargo hook assembly

ABSTRACT

An automatically releasing cargo hook having an eccentrically mounted locking mechanism which must be rotated intentionally a predetermined amount before the load may drop. Two overcenter lines of action cause positive locking. A modification of the basic hook provides an automatic pickup capability, with pairs of hook elements, locking and release mechanism being symmetrically disposed on opposite sides of the axis of the cargo hook.

United States Patent [72] inventor [2 i Appl. No. [22] Filed [45] Patented [73] Assignee [32] Priority Jack Coblenz Vancouver, B.C., Canada 737,783

June 17, 1968 Apr. 20, 1971 Okanagau Helicopters Ltd. Vancouver, B.C., Canada Aug. 24, 1967 [33] Canada [54] CARGO HOOK ASSEMBLY 10 Claims, 9 Drawing Figs.

US. Cl 294/83 B64d 17/38,

B660 H34 [50] Field ofSearch 294/82, 83, 83.]

[56] References Cited UNITED STATES PATENTS 2,430,940 1 l/ l 947 Leland 294/83(.1 2,595,450 5/1952 Coffing 294/ 83 3,207,480 9/1965 Fulton 294/ 83 Prinmry Examiner-Harvey C. Homsby Assistant Examiner-Douglas D. Watts Attorney-Cushman, Darby & Cushman ABSTRACT: An automatically releasing cargo hook having an eccentrically mounted locking mechanism which must be rotated intentionally a predetermined amount before the load may drop. Two overcenter lines of action cause positive locking. A modification of the basic hook provides an automatic pickup capability, with pairs of hook elements, locking and release mechanism being symmetrically disposed on opposite sides of the axis of the cargo hook.

PATENTEflAPazolsn $575,459

sninunrs FIG.4

PATENTED APnzo I97! SHEET 8 BF 8 FIGS I WW

This invention relates generally to a cargo hook assembly. More particularly, 7 the present invention provides an automatically releasing cargo hook suitable for use with cranes, or the like, and is especially adaptable for helicopters.

Cargo books of different types of construction and function, have long been known. However, in order to improve upon their usefulness, it has been necessary to provide means whereby such cargo hooks may pick up or release a load either partly or wholly automatically. The advantages gained by developing such a book are particularly evident when helicopters, for example, are utilized for transporting loads to remote areas, where such loads would be set down preferably without requiring .the attendance of ground personnel. A load which is usually picked up at a supply depot can readily be connected to the cargo hook carried by the helicopter, by the ground crew who lift a pickup ring for the load and place it onto the cargo hook. However, when the load is to be set down it is not unusual to encounter a lack of personnel on the ground to release the load.

in a similar manner, it is often desirable to be able to pick up a load from the ground merely by directing a cargo hook into contact with the pickup ring so provided for such load, also without requiring the assistance of ground personnel. It will be evident that in this or the above-described situation, a cargo hook which may be used to pick up a load automatically, and/or release the load automatically, that is, without assistance from ground personnel, would be a decided advantage.

It is, therefore, an object of the present invention to provide a cargo hook assembly which enables an operator to automatically release the load being carried without needing ground personnel to make contact with the load.

Another object of the present invention is to provide a cargo hook assembly which facilitates the automatic pickup of a load without the need for assistance from ground personnel.

it is yet another object of the present invention to provide a cargo hook assembly which utilizes a locking mechanism wherein positive locking action is provided.

These and other objects and features of the present invention may be embodied in a cargo hook assembly for carrying a load in suspension from a supporting structure, said cargo hook assembly comprising, a frame; automatic hook means pivotally mounted on said frame, and biased toward a load carrying position; eccentric locking means pivotally mounted on said frame and operable for locking said hook means in said load carrying position, said locking means including locking plate means; and release means mounted on said frame and actuatable for effecting the release of said locking means for enabling said hook means to pivot to a load releasing position under a force inherently applied, to said hook means by said load.

In another form embodied by the present invention, there is provided a cargo hook assembly for carrying a load in suspension from a supporting structure, said cargo hook assembly comprising, a frame; automatic hook means pivotally mounted on said frame and biased toward a load carrying position; eccentric locking means pivotally mounted on said frame and operable for locking said hook means in said load carrying position, said locking means including locking plate means; and release means mounted on said frame and actuatable for effecting the release of said locking means for enabling said hook means to pivot to a load releasing position under a force inherently applied to said hook means by said load; said frame including two arms forming a generally U-shaped configuration, with a pair of said hook means, said eccentric locking means and said release means being symmetrically mounted on respective arms such that each arm is substantially a mirror image of the other.

it will be evident that the cargo hook assembly embodied in the present invention may be utilized conveniently in most applications where cargo hooks are required. This is particularly so in situations where loads are to be picked up and/or released automatically without requiring the assistance of personnel other than the operator. Accordingly the present cargo hook assembly may be suspended from a supporting structure such as an overhead rail, on the end of a boom carried by a vehicle, and particularly as attached to a boom carried by a helicopter. In other words, a preferred form of the present invention may be embodied in the combination of a cargo hook assembly for carrying a load in suspension from a supporting structure, said cargo hook assembly comprising, a frame; automatic hook means pivotally mounted on said frame, and biased toward a load carrying position; eccentric locking means pivotally mounted on said frame and operable for locking said hook means in said load carrying position, said locking means including locking plate means; and release means mounted on said frame and actuatable for effecting the release of said locking means for enabling said hook means to pivot to a load releasing position under a force inherently applied to said hook means by said load; said frame including two arms forming a generally U-shaped configuration, with a pair of said hook means, said eccentric locking means and said release means being symmetrically mounted on respective arms such that each arm is substantially a mirror image of the other; and a collapsible boom comprising a first arm section pivotally mounted on said supporting structure, said first arm section including an offset pivotal joint located generally centrally thereof for enabling collapsing of said boom; and a second arm section for receiving said first arm section; winch means carried by said second arm section and operable for raising and lowering said first arm section for positioning said cargo hook assembly carried by the free end of said first arm section, for automatic pickup of the load.

In the accompanying drawings which illustrate a cargo hook assembly according to the present invention,

FIG. l is a plan view of an automatically releasing cargo hook assembly, with the top cover of such hook broken away to show the component parts thereof in a load carrying position;

FIG. 2 is a plan view of an automatically releasing cargo hook assembly, showing the component parts thereof in a load releasing position in outline only;

FIG. 3 is a plan view partly schematic to show the lines of action, and how the same are restrained by the rotary eccentric locking mechanism of the cargo hook assembly;

FIG. d is an elevation view taken in section along line M of FIG. 1;

FIG. 5 is an elevation view taken along line 5-5 of FIG. 1;

FIG. 6 is a pictorial view showing another embodiment of a cargo hook assembly according to the present invention, and FIG. 6a is a pickup sling, both the cargo hook assembly and pickup sling being carried on a collapsible boom carried by a helicopter;

FIG. '7 is a plan view of the cargo hook assembly of FIG. 6, with the top cover of the hook assembly removed; and

FIG. b is an elevation view taken along line M of FIG. 7.

With reference to FIGS. l5, the cargo hook assembly is shown generally at l, and consists of a frame It), a hook 20, a rotary eccentric locking mechanism 40 and a release mechanism shown generally at 80.

The frame lb of the hook assembly 1 consists of front and back cover plates 12 and 14 spaced apart and interconnected by peripheral sidewalls T6. The front and back cover plates 12 and M are provided with apertures located in predetermined positions relative to the outer dimensions of said frame, in order to receive fastening means, and pivot pins to be described later. The hook assembly 1 is provided with suitable shackles (not shown) or similar supporting means in order to suspend the hook assembly from a supporting structure.

The hook 20 is pivotally mounted on the frame 10 by means of pivot pin 22, and is continuously biased into a load carrying position by means of tension spring 24. Counterweights (not shown) suitably placed or carried on the hook 20 may be used alternatively to bias the hook to its load carrying position. If the tension spring 24 or it's equivalent biasing means were lacking, the hook 20 would hang freely in a load releasing position. The hook 20 includes a heel section 26 for contacting the rotary locking mechanism 40, and a tongue or lip section 28 which is contacted by a keeper arm 30 pivotally mounted on the frame by means of pivot pin 32. The keeper arm 30 is biased into continuous engagement with the lip section 28 of book 20 by means of the spring member 34. The keeper arm 30 includes front and back members 30A and 30B, and front sidewall 30C integrally connected to be substantially U-shaped in cross section. This keeper arm 30 functions in a conventional manner to prevent accidental dislodgement of a load pickup ring 31.

The rotary locking mechanism 40 includes a pivot pin 42 for eccentrically and rotatably mounting such locking mechanism on the frame 10 of the hook assembly 1. The rotary locking mechanism 40 also includes front and back plate elements 44 and 46, and a load bearing body portion 48 so constructed as to provide for relative motion between the front and back plate elements 44 and 46 and the body portion 48. A locking plate 50 is rigidly connected to the top plate element 44 by means of conventional fastening means, such as screws 52. The locking plate 50 is provided with an upstanding shoulder pin 54 and a shoulder stop 56, both being located along the periphery thereof. As previously noted, the locking plate 50 is rigidly connected to the top plate element 44, and both are mounted for rotation relative to the frame 10 by means of the pivot pin 42. The interior structure of the rotary locking mechanism 40 includes needle bearings (not shown) suitably supported by the locking plate 50 and a rear support plate 51, in order to provide for the rotational motion of the load bearing body portion 48 relative to the locking plate 50. A convenient way of providing such relative rotary motion is shown and described in U.S. Pat. No. 2,870,5 10 issued to E. F. Morrow on Jan. 27, 1959. Accordingly, it is believed that no further description relating to the inner structure of the present rotary locking mechanism 40 need be included herein.

The present rotary locking mechanism 40 also includes front and rear locking arms 58 and 60 rotatably mounted on the frame 10 by means of a pivot pin 62. The pivot pin 62 is located adjacent one end of the locking arms 58 and 60, while a transverse cross member 64 interconnects the other, free ends of the locking arms. A tension spring 66 biases the locking arms 58 and 60 in a counterclockwise direction, to maintain the transverse cross member 64 in contact with the heel section 26 of the hook 20. The locking arm 58 is provided with an inwardly facing raised shoulder portion 68 terminating in a stepped camming surface 70. A step 72 on the camming surface 70 is engageable by the shoulder pin 54 of the locking plate 50 to maintain the eccentric locking mechanism 40 in a load releasing position, against the biasing force of a tension spring 74 which tends to pull the eccentric locking mechanism into a load carrying position as shown in H6. 1.

The release mechanism 80 comprises a somewhat wedgeshaped release arm 82, rotatably mounted on a fixed pivot pin 84 which is carried by the frame 10. The pivot pin 84 is located adjacent one end of the base 86 of the wedge-shaped release am 82, and a second, movable pivot pin 88 is carried adjacent the other end of base 86. A second, elongated release arm 90 is connected at opposite ends thereof to the fixed pivot pin 84 and the movable pivot pin 88. An intermediate connecting link 92 is rotatably connected to the movable pivot pin 88 adjacent to the elongated release arm 90 (or alternatively, adjacent arm 82), and is also connected by means of a pivot pin 94 to the free end of a solenoid crank arm 96 fixed to be driven by a solenoid shaft 98 extending from a solenoid 100 into the interior of the frame 10 of the hook assembly 1. The solenoid 180 may be selectively actuated and driven counterclockwise in order to effect the release of the rotary locking mechanism 40 and the subsequent pivoting of the hook 20 to its load releasing position, to permit dropping of the load. The rotary solenoid 180 may be either spring biased, or powered to return to its neutral position before the next actuation thereof. In order to permit the resetting of the rotary solenoid 100, irrespective of the position of the elements making up the release mechanism 80, such as that occurring when the hook 20 is held in the load releasing position, the intermediate connecting arm 92 is provided with a slot 102 which is slightly wider than the thickness of pivot pin 94, thus permitting easy sliding motion of the pivot pin 94 in the slot 102, such as occurs when the solenoid resets itself.

The release arm 82 is provided on it's inner side with a camming surface 104 including a step face 106. This step face 106 is normally in full face locking engagement with the shoulder stop 56 provided on the locking plate 50, for maintaining the hook 20 in its load carrying position. A tension spring 108 is connected to the release arm adjacent the movable pivot pin 88, or ,to release arm 82 adjacent the pivot pin 88, for urging the release arms 82 and 90 into locked position, that is, a position holding the hook 20 locked in the load carrying position. This tension spring 108 is one of the primary locking springs as will become evident from the description below relating to the operation of the hook assembly 1.

When a load is being carried by the cargo hook assembly 1, the point of contact of the heel section 26 of the hook 20 relative to the line of centers of the pivot pins 22 and 42 is approximately 10 left of center as seen in FIG. 3, thus preventing the hook 20 from opening. The rotating force as applied to the eccentric locking mechanism 40 and particularly to its body portion 48, from the heel 26 of the loaded hook 20 is restrained by the full face locking engagement of the step face 106 of the release arm 82 and the shoulder stop 56 of the eccentric locking mechanism 40. This full face locking engagement imparts an upward or clockwise force on the release arm 82 relative to its fixed pivot pin 84. This upward force is checked or restrained by the shoulder pin 54 secured to the locking plate 50 of the eccentric locking mechanism 40. This upward force is further checked by virtue of the fact that the respective lines of action through the centers of the pivot pin 84, the point of contact on the shoulder pin 54, and the full face locking engagement of the step face 106 with the shoulder stop 56, form an overcenter lock as indicated in FIG. 3.

To release the hook 20 the solenoid is actuated, to swing the release arm 82 clockwise relative to its fixed pivot pin 84. Rotating about this fixed pivot pin 84, the peripheral edge surface 83 of the release arm 82, in effect, rolls on the shoulder pin 54 through approximately 10, up to a point where the shoulder pin has moved, by virtue of the eccentric mounting of locking mechanism 40, a sufficient distance to allow the hook 20 to take up a position where the point of contact of the heel section 26 of the hook 20 with the locking mechanism is exactly on the line of action between the hook centerline and the eccentric locking mechanism centerline, i.e., on a line passing through pivot pins 22 and 42. At this point the hook 20 continues moving on in rolling contact with the eccentric locking mechanism 40, driving the latter together with the shoulder pin 54 to the left, that is, counterclockwise relative to pivot pin 42, such that the shoulder pin 54 is brought into engagement with the step 72 on the locking arm 58, preformed to receive this shoulder pin 54. The shoulder pin 54 is held in this position, consequently holding the eccentric locking mechanism 40 in an open or load releasing position until such time as the hook 20, having released its load, is pulled back into position by the tension spring 24, tripping the locking arms 58 and 60. As the hook 20 returns to its load carrying position, its heel section 26 strikes the crossmember 64 of the locking arms 58 and 60 moving the same clockwise relative to the pivot pin 62. This movement releases the shoulder pin 54 from the step 72, and due to the fact that the eccentric locking mechanism 40 is biased for clockwise rotation by the tension spring 74, the shoulder pin 54 is able to swing clockwise coming to rest bearing against the peripheral edge surface 83 of the release arm 82, again holding the whole of the locking mechanism 40 in its locked position. It should be noted that because of the approximately 10 of swinging motion of both the heel 26 in contact with the rotary locking mechanism 48, and the full face locking engagement of step face 186 with the shoulder 56, there is, in effect, a safety margin of approximately l0 of swing provided before the locking "mechanism 48 is released to permit dropping of the load. This is important since it prohibits accidental release of the locking mechanism by mere impact against the hook 28. Accordingly, a positive locking action is provided.

Another embodiment of a cargo hook assembly according to the present invention is shown in FIG. 6. The latter shows somewhat pictorially, a helicopter 286 which has connected to its fuselage a hook 282, for releasably supporting a collapsible boom assembly 284. The collapsible boom assembly 264 consists of a carrier member 286 which is substantially U- shaped in cross section, and is provided at one end with a shackle means 288 for connecting the same to the hook 282. The other end of the carrier member 286 is provided with a pair of forklike support arms 210. A pair of laterally oriented tension cables 232 are connected to the fuselage of the helicopter 286, while the free ends of such cables 212 are interconnected by means of an intermediate tensioner bar 214. This intermediate tensioner bar 214 is normally disposed above thecarrier member 286 and below the forklike support arms 218, for supporting such carrier member. In addition, the carrier member 286 is provided with a motor 205 having slipping clutches therein, a drum of windup cable 207, and sprocket and chain means 2409 interconnecting'the motor and thedrum, for facilitating raising and lowering of a collapsible boom 220. The collapsible boom 220 consists of two sections 222 and 224, the former being pivotally connected to the end 298a of the carrier member 286. The boom sections 222 and 224 are pivotally interconnected by means of an offset pivot joint 226, in order to assure that the boom will collapse at all times, especially, for instance, on any such occasion when the boom, in its fully extended, and down position, comes in contact with the ground or other solid structure, thus preventing the collapsible boom 228 from being driven up into the fuselage of the helicopter 288. The end of the boom section 224 opposite the pivotal joint 226 is provided with a swivel joint 228, to which a boom hook 238 is connected.

The swivel joint 228 is constructed of steel and is designed to carry the same full load carried by the boom hook 238. The swivel joint 228 is completely sealed, and electrical contact .between the boom hook 236 for actuation thereof and the collapsible boom 228 is made by means of copper strips mounted in a fixed block within the swivel unit 228. This block (not shown) is in two parts, one located on each side of the swivel unit 228. The purpose of using two blocks being that upon failure of one contact there always remains another contact to maintain continuity of a path for the electric current to the hook 238. The swivel unit 228 when used in the application shown in MG. 6, permits the helicopter to fly at high speed without entanglement of the load being carried. That is to say, when a helicopter is carrying a load, there is usually a cargo sling connected to the cargo hook, and because of wind forces on the cargo there is a tendency for the latter to spin. Consequently, if a swivel joint is not used, and the hook is rigid or semirigid, the cables of the cargo sling tend to wind up to such an extent that the eye of the cable will secure itself to the hook body, thereby preventing release of the load.

The following description relating to the structural detail of the boom hook 238 may be best understood with reference to NUS. 7 and 8. The boom hook 238 consists basically of a frame 232, substantially U-shaped in cross section with extensions 234 and 235 forming the arms of the U. The frame 232 includes front and back cover plates 236 and 238 and side cover plates 24 8. The side plates 248 may be fastened to the back cover plate 238 by conventional fastening means 242, or may be formed integral therewith. Mounted in the frame 232 are a pair of hooks 258, a pair of eccentric rotary locking mechanisms 280 and a corresponding pair of release mechanisms 384). Each of the pair of hooks 258, the locking mechanism 288 and the release mechanisms 380 is mounted on the respective extensions 234 and 235, such that the elements positioned on one side of the centerline 231 of the boom hook 236 form substantially a mirror image of the corresponding elements on the other side of the centerline.

More specifically, each of the hooks 250, of which the left one will be described, is made up of two generally elongated hook sections 252 and 254, pivotally interconnected by means of a pivot pin 256 which is suitably supported by means of the extension 234 of the boom hook 238. A biasing spring 258 has one end thereof embracing the hook section 254 while the center and other end of the spring member 258 cooperate with pins 259 projecting from the hook section 252 to bias the two hook sections 252 and 254 to the position shown in FIG. 7. A tension spring 260 is connected to the extension 234 at one of its ends and to the hook section 252 at its other end. The tension spring 260 is connected to the hook section 252 at a point to the left of pivot pin 256, as seen in FIG. 7 and therefore, biases the hook section 252 in a counterclockwise direction relative to the pivot pin 256. The end of hook section 252 beyond the pivot pin 256 is provided with an inwardly facing shoulder stop 262, against which the hook section 254 abuts when carrying a load. In order to provide for automatic pickup or engagement of the boom hook 230 with a pickup ring 255 so provided on a load, the hook section 254 is rounded at 264 adjacent to the pivot pin 256 which connects the two hook sections together. Accordingly, it can be seen from FIG. 7 that the hook section 254 may be swung counterclockwise against the biasing force of the spring member 258 sufficiently far to permit entry of the pickup ring 255 into the space between the two extensions 234 and 235 of the boom hook 230. After the pickup ring 255 has swung the section 254 counterclockwise relative to the pivot pin 256 and clears the end thereof, the spring member 258 urges the hook section 254 back to its load carrying position, as shown in FIG. 7. The end of hook section 252 remote from the pivot pin 256 is provided with a pivot pin 266 for rotatably mounting a roller member 268.

The eccentric rotary locking mechanism 280 of the boom hook 230 is basically identical both in structure and operation as the eccentric locking mechanism 48 of the cargo hook assembly ll shown in FIGS. l5. Hence, the rotary eccentric locking mechanism 286 is eccentrically mounted for rotation on a pivot pin 282 which is suitably mounted on the frame 232 of the boom hook 238. The rotary locking mechanism includes a body portion 284 which is engaged by the roller member 268 of the hook section 252, and is mounted for rotation on needle bearings (not shown), such needle bearings beingsuitably supported by means of front and back plates 286 and 287. As in the case of the rotary locking mechanism 40 of the embodiment of HG. l, the internal structure of the rotary locking mechanism 280 is basically the same as shown in the rotary locking mechanism of the above-mentioned Morrow patent.

The front plate 286 of the locking mechanism 280 includes a shoulder stop 288 formed on the outer, peripheral edge thereof, and a shoulder pin 298 projecting upwardly from the plane of the plate 286 and being connected to the same at the periphery thereof. A tension spring 281 interconnects the frame 232 of the boom hook 230 to the rotary locking mechanism 288, to bias the latter in a clockwise direction relative to the fixed pivot pin 282. That is, the tension spring 2811 urges the rotary locking mechanism 280 continuously to assume a positively locked position. Also included in the rotary locking mechanism 280 is a pair of locking arms 292 and 293, of which the arm 292 is provided with a step 296 on an edge 297 thereof facing the rotary locking mechanism 280, such locking arms being interconnected at one end by means of the pivotal attachment of each to a pivot pin 294 supported by the frame 232, and at the free other ends by means of a transverse member 298. The purpose and operation of the locking arms 292 and 293 is identical to the locking arms 58 and 60 of the embodiment of HO. 1, and will be described below.

The release mechanism 300 includes a somewhat V-shaped release arm 302 pivotally mounted on, and supported from the frame 232 by means of a pivot pin 304 fixedly supported by the latter, such release arm 302 being urged in a counterclockwise direction relative to the fixed pivot pin 304 by means of a tension spring 306. The release arm 302 is provided with a camming outer surface 308 which engages the shoulder pin 290, and a step face 310 which is engaged by the step shoulder 288 on the plate 286, in full face locking engagement. The outer camming surface 308 may be considered to be on one arm of the generally V-shaped release arm 302, while a movable pivot pin 312 is provided adjacent the end of the other arm. An intermediate connecting link 314 is slotted at 316 adjacent one end thereof and is pivotally interconnected with the release arm 302 by means of the movable pivot pin 312. The slot 316 in the intermediate connecting link 314 is engaged by a pivot pin 318 provided on the free end of a solenoid crank arm 320, the latter being rigidly connected to and driven by a drive shaft 322 of a rotary solenoid 324. As in the embodiment of FIGS. 1-5, the rotary solenoid 324 may be either spring urged or powered to reset, that is to return to its neutral position before the next actuation thereof. The sliding engagement between the pivot pin 318 and the slot 316 of the freely movable intermediate connecting link 314 permits resetting of the rotary solenoid 32 i, irrespective of the position in which the release arm 302 may be held, for instance, when the release arm 302 is held in a load releasing position by the hooks 250 being held open.

Although the embodiment of FIGS. 7 and 8 shows the use of two rotary solenoids 324, a single rotary solenoid may be used alternatively, with suitable linkages being provided to actuate the release arms 282 of each of the release mechanisms 300. Similarly, the end of one of the hook sections 254 is shown in FIG. 8 as being of a reduced thickness in order to be received within a recess defined between the two prongs of the forked end of the other hook sections 254. Alternative cooperating arrangements may be utilized equally well to provide the desired working arrangement and cooperation of the hook sections 254.

In operation, the boom hook 230 as illustrated in FIGS. 7 and 8 will be carried on the free end of a collapsible boom carried by a helicopter in a preferred arrangement, or alternatively on the free end of a boom mounted on a motor vehicle. In either instance, it is necessary only to direct the boom hook 230 of the present invention into contact with a pickup ring so provided on a load, with the pivotal hook section 254 being swung inwardly to permit automatic engagement with the pickup ring. As indicated above, the pivotal hook sections 254 are biased to a load carrying position by means of a spring element providedfor that purpose, with the weight or applied force of the load being transmitted through the hook section 25% onto the abutment shoulder 262 of the other hook section 252 and subsequently through the roller member 268 and against the rotary locking mechanism 280. From FIG. 7 it can be seen that the line of action of the force acting through the point of contact between the roller 268 and the body portion 284 of the rotary locking mechanism 280 is to the right, i.e., over center of a line drawn between the fixed pivot pins 256 and 282 of the hook 250 and rotary locking mechanism 280 respectively. Furthermore, positive locking of the hook 250 in the position shown in FIG. 7, is assured by virtue of the line of action of the full face locking engagement between the shoulder stop 288 and the step shoulder 310 of the release arm 302 being over center of a line passing through the fixed pivot pin 304 and the point of contact between the shoulder pin 290 and the camming outer surface 308 of the release arm 302. This over center nature, and direction of the lines of action here described is essentially identical to that described in connection with the locking mechanism 40 of the cargo hook of FIGS. 1-5. Positive locking of the hooks 250 in their load carrying position is again assured.

In order to drop or set down the load, the pilot of the helicopter, or another operator may actuate the rotary solenoids 324 to cause pivoting of the solenoid crank arm 320 clockwise relative to the crankshaft 322, and subsequent clockwise rotation of the release arm 302 relative to its fixed pivot 304 thereby disengaging the full face locked engagement of the shoulder stop 288 with the step shoulder 310. More specifically, as the release arm 302 swings in a clockwise direction, the shoulder pin 290 moves in rolling contact with the camming outer surface 308 of the release arm, until such time as the point of contact between the roller member 268 with the body portion 284 of the rotary locking mechanism 280 has traversed an angular distance of some 10 to a location which is colinear with a line through the pivot pins 256 and 282. At this point, the shoulder stop 288 and step shoulder 310 of the rotary locking mechanism 280 and the release mechanism 300 respectively, are completely disengaged, to permit swinging of the hook 250 clockwise relative to the fixed pivot pin 256 to permit releasing of the load. As the hook 250 is swinging in a clockwise direction, rolling contact is maintained between the roller member 268 and the body portion 284 of the rotary locking mechanism 280 for such time as the rotary locking mechanism 280 and shoulder pin 290 carried thereon are being pivoted counterclockwise relative to the fixed pivot pin 282, bringing the shoulder pin 290 into engagement with the step 296 on the locking arm 292 thereby to lock or retain the rotary locking mechanism 280 in a load releasing position. The front and rear locking arms 292 and 293 are biased by means of a spring (not shown) in a counterclockwise direction relative to their fixed pivot pin 294. It is essential that the front locking arm 292 engages the shoulder pin 290 of the rotary locking mechanism to retain the latter in a load releasing position, since the rotary locking mechanism would otherwise be biased to swing back to a load carrying position by virtue of the constant urging of tension spring 281. If this were permitted to occur, the hook section 252 would be unable to swing back to its normal position, as shown in FIG. 7, since the roller member 268 would come into contact with the rotary locking mechanism 280 on the wrong side thereof, that is, on the side of the latter closest to the centerline 231 of the boom hook 230, thus leaving the hooks 250 in a load releasing position.

It is important to realize that in the foregoing description, directions have been referred to as being either clockwise or counterclockwise. These directions are to be taken with respect to pivot pins located on the left half of the cargo hook 230 of FIG. 7, that is, to the left of the centerline 231. As indicated above, the right-hand half of the cargo hook 230 is substantially a mirror image of the left-hand half however, the directions of rotation, or swinging motions, will be reversed to those described in relation to the operation of the corresponding components in the left-hand half of the bottom hook 230. In other words, a rotary or swinging action which is described as being counterclockwise with respect to elements in the left-hand portion of the cargo hook, will, in fact, be clockwise when considered in the right-hand half of the boom hook 230.

Although it is not shown in FIGS. 1, 7 or 8 herein, both the cargo hook 1 and the boom hook 230 will be provided with a manual override, which may be actuated to effect release of the load, in the event of power failure or other inoperability of the rotary solenoids. In addition, microswitches 330 are provided as shown in FIGS. 1 and 7 to indicate by means of a signal light or the like to the pilot or operator that the hook is either locked in a load carrying position, or that it is not.

As previously indicated with respect to the cargo hook shown in FIGS. I-5, it is to be noted that because of the approximately 10 of swinging motion required of both the rotary member 268 contacting the locking mechanism 280, and the full face locking engagement of the step face 310 with the shoulder step 288, there is, in effect, a safety margin of approximately 10 provided before the locking mechanism will permit releasing of the load. Such a safety margin, therefore, prohibits the accidental release of the locking mechanism by major impact against the boom hook 230. Accordingly, a positive locking action is provided.

Furthermore, although the pickup ring 255 may be of conventional design FIG. ha shows a preferred form thereof. That is, the pickup ring 255 preferably comprises a pair of overlapping rings made of a braided nylon rope, for instance, the overlapping rings being disposed to be generally mutually perpendicular. in addition, each of the overlapping rings includes at least one loop 255a therein, with one of the loops of each ring extending through one of the loops of the other ring, thereby locking such rings together. A pickup ring of this general type can be approached from virtually any side thereof and still enable automatic engagement with the boom hook 23th to pick up the load.

Thus, the present invention provides a cargo hook assembly having a positive locking action, an automatic release and/or pickup facility, and being adaptable for a wide variety of uses. in the preferred embodiment, cargo hook l may carry loads of the order of 2000 lbs., while the boom hook 230 may carry loads of the order of 4000 lbs. Obviously, the usual design and safety factors will be incorporated into the manufacture of the cargo hook assembly of the present invention thus providing the same with a wide range of capabilities. From a practical point of view, basically only the materials of which the component parts of the hook shown herein are made needs to be changed in order to increase or decrease the load carrying capability within a wide operating range. This latter is, of course, also dependent upon the exact nature and load capacity of the vehicle or-aircraft with which the above cargo hooks are to be used.

Furthermore, it should be clearly noted that the cargo hook assembly as illustrated and described herein can be released by the pilot, or other operator, and is not a fixture, i.e., part of the supporting structure to which it is attached. The present cargo hook assembly may be used on any aircraft or helicopter, overhead rail or vehicle-mounted boom without modification. Various means are well known in the art for attaching the present, or any cargo hook assembly, to the particular type of support structure which it is being used.

llclaim:

l. A cargo hook assembly for carrying a load in suspension from a supporting structure, said assembly comprising:

a frame having a hook pivotally supported thereon and biased to an operative load carrying position, said hook including a heel section;

locking mechanism mounted on the frame to be eccentrically rotatable and being operable to generate a positive over-the-center locking action to maintain the hook in said operative position, said mechanism including a body portion for engaging the heel section of said hook for holding the latter locked, a locking plate that is movable relative to said body portion and being provided with stop pin means and a shoulder stop, and retaining means pivotally mounted on the frame that are provided with step means engageable with the stop pin means when the load is to be dropped to hold the locking mechanism in an inoperative, load releasing position;

an actuating device supported on the frame; and

release means movably mounted on the frame and operatively connected to the actuating device, and having a stepped face that is engageable with said shoulder stop for enabling the hook to be maintained in said operative position, said release means being operable upon activation of the actuating device to effect releasing the locking mechanism which then rotates through a predetermined angle before allowing the hook to pivot unrestrainedly to drop the load.

2. The cargo hook of claim 1, wherein said locking action is provided by an over-the-center positioning of lines of force developed by the contact between the body portion of the locking mechanism and said heel section relative to a line joining the centers of rotation of the locking mechanism and said hook.

3. The cargo hook assembly of claim l, wherein there is a reinforcement of said locking action provided by an over-thecenter positioning of lines of force developed by contact between said shoulder stop and said stepped face, between said shoulder pin and a peripheral surface on said release means, and a center of rotation of the release means.

4. The cargo hook assembly of claim 1, wherein the retaining means and the release means are pivotally movable about separate centers of rotation.

5. A cargo hook assembly for carrying a load in suspension from a supporting structure, said assembly comprising a frame having a hook pivotally supported thereon and biased to an operative, load carrying position, said hook including a heel section; rotary locking mechanism mounted on the frame to be eccentrically rotatable and being operable to generate a positive over-the-center locking action to maintain said hook in said operative position, said mechanism including a body portion for engaging said heel section to hold the hook locked, locking plate means that is movable relative to the body portion and is provided with a shoulder pin and a shoulder stop, and retaining means pivotally supported on the frame and having a step thereon engageable with said shoulder pin when the load is to be dropped to hold said mechanism in an inoperative, load releasing position;

an actuating mechanism supported on the frame; and

a release means operatively connected to the actuating mechanism and movably mounted on the frame for pivotal motion having a stepped face that is engageable with said shoulder stop to enable the locking mechanism to maintain the hook in said operative position, the release means being operable upon activation of the actuating mechanism to effect releasing the locking mechanism which then rotates through a predetermined amount before allowing the hook to pivot unrestrainedly to drop the load.

6. The cargo hook assembly of claim 5, wherein the frame comprises a body section and two arm sections disposed in a U-shaped form, with each arm section being provided with a hook assembly, one rotary locking mechanism, one actuating mechanism and one release means, operably disposed on the arm sections to enable automatic pickup of ring means on a sling in which the load is to be carried.

7. The cargo hook of claim 5, wherein said actuating mechanism comprises rotary solenoid means selectively operable upon activation thereof to release' the locking mechanism allowing the same to rotate a predetermined amount before permitting the hook to pivot unrestrainedly to allow the load to be dropped.

8. A cargo hook adapted to be carried on the free end of a boom, for supporting a load in suspension from a supporting structure to which the boom is connected, said cargo hook comprising:

a U-shaped frame having a body portion and two arms, each of the arms pivotally supporting a two-part hook assembly that includes a heel section, the hook assemblies each being biased to an operative load carrying position;

two rotary locking mechanism mounted on the frame each to be eccentrically rotatable and being operable to generate a positive over-the-ccnter locking action to maintain each hook assembly in .said operative position, each mechanism including a body portion for engaging said heel section to hold the hook assemblies locked, locking plate means that is movable relative to the body 5 portion and is provided with a shoulder pin and a shoulder stop, and retaining means pivotally supported on the frame and having a step thereon engageable with said shoulder pin when the load is to be dropped to hold said mechanism in an inoperative load releasing position;

actuating means supported on the frame; and

release means operatively connected to each locking mechanism and the actuating means and being movably mounted on the frame for pivotal motion, having stepped faces that are engageable with said shoulder stops to enable the hook assemblies to be maintained in said obtained following release ofiheload, to return'the hook assembly to an operative condition in which said hook assembly is in readiness, capable of carrying another load.

10. The cargo hook assembly of claim 8, wherein the retaining means and the release means are pivotally movable about separate centers of rotation. 

1. A cargo hook assembly for carrying a load in suspension from a supporting structure, said assembly comprising: a frame having a hook pivotally supported thereon and biased to an operative load carrying position, said hook including a heel section; a locking mechanism mounted on the frame to be eccentrically rotatable and being operable to generate a positive over-thecenter locking action to maintain the hook in said operative position, said mechanism including a body portion for engaging the heel section of said hook for holding the latter locked, a locking plate that is movable relative to said body portion and being provided with stop pin means and a shoulder stop, and retaining means pivotally mounted on the frame that are provided with step means engageable with the stop pin means when the load is to be dropped to hold the locking mechanism in an inoperative, load releasing position; an actuating device supported on the frame; and release means movably mounted on the frame and operatively connected to the actuating device, and having a stepped face that is engageable with said shoulder stop for enabling the hook to be maintained in said operative position, said release means being operable upon activation of the actuating device to effect releasing the locking mechanism which then rotates through a predetermined angle before allowing the hook to pivot unrestrainedly to drop the load.
 2. The cargo hook of claim 1, wherein said locking action is provided by an over-the-center positioning of lines of force developed by the contact between the body portion of the locking mechanism and said heel section relative to a line joining the centers of rotation of the locking mechanism and said hook.
 3. The cargo hook assembly of claim 1, wherein there is a reinforcement of said locking action provided by an over-the-center positioning of lines of force developed by contact between said shoulder stop and said stepped face, between said shoulder pin and a peripheral surface on said release means, and a center of rotation of the release means.
 4. The cargo hook assembly of claim 1, wherein the retaining means and the release means are pivotally movable about separate centers of rotation.
 5. A cargo hook assembly for carrying a load in suspension from a supporting structure, said assembly comprising: a frame having a hook pivotally supported thereon and biased to an operative, load carrying position, said hook including a heel section; a rotary locking mechanism mounted on the frame to be eccentrically rotatable and being operable to generate a positive over-the-center locking action to maintain said hook in said operative position, said mechanism including a body portion for engaging said heel section to hold the hook locked, locking plate means that is movable relative to the body portion and is provided with a shoulder pin and a shoulder stop, and retaining means pivotally supported on the frame and having a step thereon engageable with said shoulder pin when the load is to be dropped to hold said mechanism in an inoperative, load releasing position; an actuating mechanism supported on the frame; and a release means operatively connected to the actuating mechanism and movably mounted on the frame for pivotal motion having a stepped face that is engageable with said shoulder stop to enable the locking mechanism to maintain the hook in said operative position, the release means being operable upon activation of the actuating mechanism to effect releasing the locking mechanism which then rotates through a predetermined amount before allowing the hook to pivot unrestrainedly to drop the load.
 6. The cargo hook assembly of claim 5, wherein the frame comprises a body section and two arm sections disposed in a U-shaped form, with each arm section being provided with a hook assembly, one rotary locking mechanism, one actuating mechanism and one release means, operably disposed on the arm sections to enable automatic pickup of ring means on a sling in which the load is to be carried.
 7. The cargo hook of claim 5, wherein said actuating mechanism comprises rotary solenoid means selectively operable upon activation thereof to release the locking mechanism allowing the same to rotate a predetermined amount before permitting the hook to pivot unrestrainedly to allow the load to be dropped.
 8. A cargo hook adapted to be carried on the free end of a boom, for supporting a load in suspension from a supporting structure to which the boom is connected, said cargo hook comprising: a U-shaped frame having a body portion and two arms, each of the arms pivotally supporting a two-part hook assembly that includes a heel section, the hook assemblies each being biased to an operative load carrying position; two rotary locking mechanism mounted on the frame each to be eccentrically rotatable and being operable to generate a positive over-the-center locking action to maintain each hook assembly in said operative position, each mechanism including a body portion for engaging said heel section to hold the hook assemblies locked, locking plate means that is movable relative to the body portion and is provided with a shoulder pin and a shoulder stop, and retaining means pivotally supported on the frame and having a step thereon engageable with said shoulder pin when the load is to be dropped to hold said mechanism in an inoperative load releasing position; actuating means supported on the frame; and release means operatively connected to each locking mechanism and the actuating means and being movably mounted on the frame for pivotal motion, having stepped faces that are engageable with said shoulder stops to enable the hook assemblies to be maintained in said operative position, the release means being operable upon activation of the actuating mechanism to effect releasing the locking mechanisms which then rotate through about 10* before allowing the hook assemblies to pivot unrestrainedly and drop the load.
 9. The cargo hook assembly of claim 5, wherein biasing means are provided for the rotary locking mechanism and the release means such that an automatic self-relocking action is obtained following release of the load, to return the hook assembly to an operative condition in which said hook assembly is in readiness, capable of carrying another load.
 10. The cargo hook assembly of claim 8, wherein the retaining means and thE release means are pivotally movable about separate centers of rotation. 